Controller for electric motors.



-W. F. LENT.

CONTROLLER row ELECTRIC morons;

I APPLICATION FILED MMLZB, 1917- Patented Mar. 19, 1918.

- be embodied in other forms for control UNITED STATES PATENT OFFICE.

WILMAB, F. LENT, 0F PHILADELPHIA, PENNSYLVANIA, ASSIGNOE TO THE CUTLER- HAMMER MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

I CONTROLLER FOR ELECTRIC MOTORS.

To all whom it may concern:

Be it known that I, WILMAR F. LENT, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in Controllers-for Electric Motors, of which the following isa full, clear, concise, and exact de scription, reference being had to the accompanying drawing, forming a part of this specification.

Thisjinvention relates to controllers for electric motors and while applicable to controllers for both A. C. and D. C. motors, is particularly applicable to the former.

For example, a controller embodying the invention may be advantageously employed for slip regulation of an induction motor, by insertion of resistance in the rotor circuit of the motor under abnormal conditions and exclusion of such resistance upon restoration of normal conditions.

An object of the invention is to provide a controller forthe aforesaid and other purposes adapted to utilize a portion of the starting resistance for subsequent regulation of the motor and where parallel resistances are employed for starting, to utilize a portion of one of such resistances for regulation.

Another object is to provide for variation of the regulating portion of resistance with out- .afl'ecting the use thereof for starting purposes.

Other objects and advantages will hereinafter appear. e

The accompanying drawing diagrammatically illustrates an embodiment of the invention for control of an alternating current motor and the same will now be described,

it being understood that the invention may 0 both A. C. and D. C. motors.

More specifically, the drawing shows an alternating current motor 1 to be supplied with current from 'lines L, L and L through an electro-responsive main switch 2 controllable by starting and stopping push-buttons 3, a, said motor being controllable through the medium of resistances R, R R and R, each of the same having a plurality of sections for inclusion in all phases of the secondary circuit of said mo- .tor. The resistances are arrang d to beprogressively included in circuit n a parallel Specification of Letters Patent.

circuit.

Patented Mar.v 19, 1918 Application filed March 26, 1917. Serial 110,157,459.

relation and to be finally short-circuited for acceleration of the motor by electro-responsive switches 5, 6, 7 and 8 which are arranged to respond progressively subject to control by series relays 9, 10, 11 and 12, each having a plurality of windings for connection in all phases of the secondary circuit.

Further, the drawing showsfa resistance shunting switch 13 for limiting the amount of the resistance R to be included in the rotor circuit for slip regulation, a slip relay 14c for timing the inclusion and exclusion of said slip regulating resistance and a retarded relay 15 fo controlling a short-circuit around the'coil of said overload relay. Of the foregoing, the main switch, switches 5, 6, 7, 8 and Band relay 15 are provided with one or more sets of auxiliary contacts for governing the closing and opening of suitable maintaining and control circuits.

The circuit. connections of the foregoing switches are such that upon closure of start- -ing switch 3, main switch 2 closes for completing the motor circuit, at the same time completing a maintaining circuit for itself and closing the energizing circuit of retarded relay 15 for rendering the slip relay l4: inactive during acceleration of the motor. Closure of retarded relay 15 also completes the energizing circuit of the first accelerating switch 5, whereupon the accelerating switches 5, 6 and 7 are adapted to respond progressively, subject to delay by the respective series relays 9, 10- and 11, thereby progressively connecting the resistances R R and R in parallel in the rotor circuit. Closure of accelerating switch 7 completes the circuit of resistance shunting switch 13 which responds, subject to delay by series relay 12, for limiting the portion of the resistance R to be used for subsequent slip regulation. Closure of resistance shunting switch 18 completes the circuit of accelerating switch 8 which responds for short-circuiting all phase resistance from the rotor Closure of said switch 13 also completes a maintaining circuit for itself and, for switch 8 independent of switch 7 and iiiterrupts the closing circuit of retarded relay 15. Said relay thereafter opens, subject to dash-pot retardation, for rendering the slip relay 145 sensitix e to overloads, and also interrupting the. energizing circuit of switch 5, whereupon switches 5, 6 and 7 open progressively.

pen the occurrence of an overload in closure of resistance shunting switch Upon restoration of normal current conditions, relay 1 1 closes r again short-cireuiting said resistance through closure switch 8.

he above mentioned power circuits may be described as "follows; Line L is connected through the main switch by conductor 16 through the winding of slip relay 1%, thence by conductor to the motor. Said winding is arranged to be shunted through conductors 13 and 19 upon closure of relay 15. Line L is connected through the main switch, by conductor 20 to the motor, while line L permanently connected to the motor. The secondary lines 21, 22 and 23 extend through the respective phase sections of starting resistance 1%, through the respective phase windings of series relay 9, being interconnected therebeyond. The resistances R R ant are included in parallel branches of the rotor circuit, being connected through common conductors 2e, 25 and 26 to the secondary lines 21, 22 and 23 at a point in advance of resistance R. The windii gs of series relays 10, 11 and 12 are also included in the branch circuits, said circuits being normally open and adapted to be closed by accelerating switches 5, 6 and 7. The contacts of said series relays are arranged to remain closed during normal conditions.

Closure of resistance shunting switch serves to short-circuit through conductors 27, 28 and 29 a portion of each phase sec tion of resistance R leaving the balance thereof for subsequent slip regulation, the value of the latter being determinable at will. 0 con- Closure of accelerating switch 0 neets conductors 30, 31 and 32- for shunting all secondary resistance.

The control circuits may be traced as follows: The main switch energizing circuit is from line L by conductor 33 through the down contacts 3-l, 35, 36, 37' and 38 of the respective switches 8, 13, '7, 6 and 5,

, said contacts being respectively connected through conductors 39, e0, 41 and 42, thence by conductor e3 through starting switch 3, by conductor 44 through stopping switch 4, by conductor 45 through thewinding of said main switch, and by conductor 41-6 to line L The main switch maintaining circuit is from line L by conductor L7 through the first set of up contacts 48 of said main switch, by conductors ie and through stopping switch a, thence through the wind ing of said mainswitch to line L as above ductors and 59 toline L one down contacts or through the down contacts oi? switch 13, thence by conductors 10 and 50 through the second oi up contacts 51 of the main switch thence by conductor through the winding of said relay 15 and by conductor to line L, The energizing circuit of accelerating switch is from line L by condoctor through the first set of up con tacts or the mam switch and by conductors 1:9 and 5" through series relay 9, thence by conductor through the upcontacts'56 of relay 15, by conductor 57 through the winding of said accelerating switch and by conductors 58 and 59 to line If. The encrgizing circuit of accelerating switch (5 is from line L by conductors GO and (31 through series relay 10, by conductor (52 through the up contacts (53 of switch 5, thence by conductor (Bl through the winding of said accelerating switch (3 and by con- The energizing circuit of accelerating switch 7 is from line L by conductor 60, through series relay 11, and by conductor 66 through the up contacts 67 of switch 6, thence by conductor 63 through the winding 01 said accelerating switch and by conductor 59 to line If. he energizing circuit of resistance shunting switch 13 is from line L through the first set of up contacts of the main switch, by conductor 54: as previously traced, and by conductor 69 through series relay 12, thence by conductor 70 through the up contacts 71 of switch 7 and by conductors 72 and 73 through the windings of said switch 13, thence by conductors 7 1 and 59 to line L The maintaining circuit of said switch which is completed upon closure thereof is from line L to conductor 51, as last traced, thence by conductor 75 through the first up contacts 76 of said switch 13, by conductors 77 and 73 through the winding oi said switch to line L as previously traced. The energizing circuit of accelcrating switch 8 is from line L to conductor 72, as previously traced, thence through the second set of up contacts 78 of switch 13 and by conductor 7 9 through slip relay 1.1-, thence by conductor 80 through the winding of said accelerating switch 8 and by conducof switch 13, said relay is deenergized upon and during closure of said switch, however,

owing to dash-pot retardation, relay 15 does predetermined conditions for effecting not open until after closure of switch 8 and subsiding of the surges of current due to acceleration. in practice the das po arranged to retard only the openii U or s relay. The slip relay 1% controls the w'lding of switch 8 only switch 13 remaining closed during running of the motor.

Stopping of the motor is effected by opening stopping switch a. The circuit of sta ting switch 3 beingthrough the down con tacts of switches 8, 13, 7, (5 and 5, said start ing switch is inactive for starting the motor so long as any or" said switches ren'iains closed. v I

What I claim as new and desire to secure by Letters Patentis:

1. In a motor controller, in combination a plurality of resistances and means 'i'tor progressively paralleling and shorc-circuiting' said resistances for acceleration. and thereafter reincluding in circuit limited portion of one 01' said resistances for res lation.

said resistances whereby the remaining portion thereof maybe reincluded in circuit by said first IHQHlZlODBCl' means for speed resulat-ion. i

8. In a motor controller, in combinationf plurahty of reslstances, means tor pro gressively parallelingand short-circu L said resistances for acceleration, means partially short-circuiting one 0t said sistances whereby the 'remaining portion thereof may be reincluded i circuit by said first mentioned means for speed re ulation, and means operative automatically undo such operation of said first mentioneo means.

-'l-. in amotor controller, in combination. a plurality of resistances, means for pa 1 lieling and finally short-circuiting said resistances for motor acceleration, means for short-circuiting a predetermined portion of one of said resistances whereby the: remaining portion thereof may be reincluded in circuit by said lirst mentioned means for speed regulation, the value of said portion being variable at will, and means operative automatically under predetermined conditions for effecting such operation of first mentioned means.

5. lln a motor controller, in combination,

3 .tro responsive mea paralleling and finahy short-circuitmg sa said lir a pluralit of fixer resistance sections elec- A kl 9 as for progressl sections for motor acceleration and ti after reincl in tion of one oi said sections for regulation In a motor controller, in combinata plurality of resistances, means tor par leling ant. finally shert-circuiting said sistances motor accelcratioi'i, means 1 short-c itiug a predetermined portion one of sa resistances whereby the reins? i215 portion thereof say-be reincluded in in, circuit "by said first P entioned means speed rea'ulrlue of said porti' 'l being .vari; leans operative an; tomatically A termined conditio for eli'ecting such operation of said mentioned means ant eans.

notor controller, in combination, H sistances, elect-r0 sponsire means ;or iessively parallri V and finally sh 'n-eire hing said resistances for motor accemration, other electro-resprur sivc means for paiti ll short-circuiting o of said resistznces reby the remainii 5 portion reincluded in ci cuit by .id hrst m gtioned means, elect.. responsi e means operative under predetermined condi ions to effect such operation 98 of said first mentioned meansfor speed re23- ulation electro= 'ponsive means one tive to render said last mentioned means inactive durin motor acceleration through nod neans controller, in combination, y 0;? electro-responsive progressiv ly paralleling and finally short-ci aiiting said resistances for motor acceleration, an electro -responsive i for pa tfiully short-circuiting one of resistances where s-y the remaining portion th eof me be reincluded in circuit by said list me tioned means, means operative under pfedetermined conditions to of feet such operation of said first mentioned means for speed regulation, and means ren dering said last me stoned means ineli ec tire prior to closure of said switch and for a predetermined period thereafter. (ness whereof, I have hereunto subi m 8. an

a pl u ra n'ieans ice All H 

